The complete nucleotide sequence of the Vibrio harveyi bacteriophage VHML

Abstract

Aims: To determine the complete nucleotide sequence of the bacteriophage VHML and establish a hypothesis for the virulence conversion caused by VHML infection of Vibrio harveyi. Methods and Results: The complete nucleotide sequence of VHML was determined (43 193 bp) and used to identify putative genes. The translated products of these genes were compared with reported sequences to assign hypothetical functions. All anticipated structural genes and putative genes for lysogeny were identified. In addition, we found a complete N6-adenine methyltransferase (Dam) gene that appeared to have an essential site for ADPribosylating toxins at the C-terminal of the translated product. Conclusions: Virulence conversion of V. harveyi by VHML may be associated with Dam transcriptional regulation. The Dam gene may also encode for a toxin component similar to ADP-ribosylating toxins. Significance and Impact of Study: This manuscript lays the foundation for understanding the virulence of toxin-producing V. harveyi. Further research into aspects discussed here will lead to a greater comprehension regarding the invertebrate disease vibriosis and its control in the farming of these animals.

Biodiversity of Vibrios

“…Mortality caused by vibrios in reared fish and shellfish is very common during early larval stages and can occur suddenly, leading sometimes to death of the entire population (42,96,157,184,185,187,217,230,283,287,295). Pathogenicity of V. harveyi is associated with the presence of a bacteriophage (15,291). A bacteriological survey of cultures of sea bream (Sparus aurata L.) in Spain between 1997 and 2000 detected 25 outbreaks (450).…”

Identification and characterization of ϕH111-1

“…15 We could not identify any previously characterized phages with ≥ 40% similarity that would belong to the same genus as ϕH111-1. Currently, phages with the most similar proteomes are AcaML1 of Acidithiobacillus caldus (JX507079.1; 28.17% similar) and the "Vhmllikevirus" phages VHML of Vibrio harveyi (NC_004456.1; 28.07% similar) and both [16][17][18][19] Although these phages share subfamily-level similarity, they are very distinct with respect to aspects such as host, gene content, and lifestyle. AcaML1 lysogenizes a thermophilic and acidophilic γ-proteobacterium and has a significantly larger 59 kbp genome with two insertion sequences.…”

“…16 The "Vhmllikevirus" phages VHML, VP58.5, and vB_VpaM_MAR have similar genome sizes to ϕH111-1 (41-43 kbp) but are thought to lysogenize as linear plasmids with telomeres in Vibrio species. [17][18][19] The commonalities among ϕH111-1, AcaML1, and the "Vhmllikevirus" phages are largely restricted to the morphogenesis genes. These phages all have P2-like tail proteins, but encode capsid morphogenesis/DNA packaging and accessory proteins that are unrelated to those of P2 ( Table 2).…”

Two novel temperate bacteriophages co-existing in Aeromonas sp. ARM81 – characterization of their genomes, proteomes and DNA methyltransferases

“…Another myovirus, VHML of Vibrio harveyi (Oakey et al, 2002) that is closely related to one of the abovementioned phages, VP58.5 (Zabala et al, 2009) also contains genes encoding homologues of the N15-like protelomerase (Ravin, 2015) and partitioning protein ParA (Oakey et al, 2002). VHML was initially described as a prophage integrated into the host chromosome (Oakey et al, 2002), but later it was suggested that it may be a linear plasmid-like prophage as well (Lima-Mendez et al, 2008). VHML was recently included into the family of N15-like linear phage-plasmids (Ravin, 2015).…”